#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
using namespace std;
class Solution
{
public:
    class Sum
    {
    public:
        Sum()
        {
            _ret += _i;
            _i++;
        }

    };
    int Sum_Solution(int n)
    {
        Sum a[n];
        return _ret;
    }
private:
    static int _i;
    static int _ret;
};

int Solution::_i = 1;
int Solution::_ret = 0;